British Journal of Nutrition

Energy Metabolism

Discrepancies between energy intake and expenditure in physically active women

Kathleen Mulligana1 and Gail E. Butterfielda1*

a1 Department of Nutritional Sciences, University of California, Berkeley, CA 94720, USA


Energy intake and expenditure in women runners and non-runners were assessed by weighed food records, evaluation of minute-by-minute activity diaries, and indirect calorimetry. All participants were adapted to their stated activity levels for at least 6 months and maintained a constant body-weight throughout their participation. Calculated daily energy intake equalled calculated expenditure in non-runners (7300 (SD 1536) v. 7476 (SD 872) kJ/d), but calculated energy expenditure in women running about 54 km/week was found to exceed intake by more than 2700 kJ/d (8259 (SD 1466) v. 10963 (SD 1367), P < 0.01). The runners showed no evidence of compensating for the increased energy expenditure associated with running by engaging in lower-intensity activities during non-running time. Further, runners did not decrease energy expended at various activities. The findings suggest that women adapted to high levels of activity may possess mechanisms to maintain body-weight without significantly increasing energy intake.

(Received October 30 1989)

(Accepted January 19 1990)


* For reprints.

† Geriatric Research, Education and Clinical Center, 182B, Palo Alto Veterans Administration Medical Center, Palo Alto, CA 94304, USA.